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opdA , a Salmonella enterica Serovar Typhimurium Gene Encoding a Protease, Is Part of an Operon Regulated by Heat Shock

C A Conlin、Charles G. Miller2000-01-15Journal of Bacteriology

The opdA (prlC) gene of Salmonella enterica serovar Typhimurium and Escherichia coli encodes the metalloprotease oligopeptidase A (OpdA). We report that opdA is cotranscribed with a downstream open reading frame, yhiQ. Transcription of this operon is induced after a temperature shift (30 to 42 degrees C), and this ind…

Bacterial Genetics and BiotechnologyEnzyme Structure and FunctionCancer Research and Treatments

Bismuth selenide iodide

Thomas Braun、Francis J. DiSalvo2000-01-15Acta Crystallographica Section C Crystal Structure Communications

BiSeI crystals obtained by a chemical-transport reaction are orthorhombic (space group Pnma) with a = 8.6967 (17) Å, b = 4.2205 (8) Å and c = 10.574 (2) Å. It could be confimed that BiSeI crystallizes in the centrosymmetric SbSI structure type.

Crystal Structures and PropertiesSolid-state spectroscopy and crystallographyInorganic Chemistry and Materials

Charge transfer and memory loss in keV oxygen-ion scattering from Cu(001)

Andone C. Lavery、C. E. Sosolik、C. Keller 等 4 位作者2000-01-15Physical review. B, Condensed matter

Oxygen ion and neutral atom yields were measured for ${\mathrm{O}}^{+}$ and ${\mathrm{O}}^{\ensuremath{-}}$ ions incident on a clean Cu(001) surface for ion energies from 0.4 to 5 keV. Scattering geometries were chosen that simplify the selection of single collisions between the incident ions and surface atoms and con…

X-ray Spectroscopy and Fluorescence AnalysisElectron and X-Ray Spectroscopy TechniquesIon-surface interactions and analysis

Studies of local structure of Cm3+ in borosilicate glass using laser and x-ray spectroscopic methods and computational modeling

G. K. Liu、V. V. Zhorin、Mark R. Antonio 等 6 位作者2000-01-15The Journal of Chemical Physics

The local environment of Cm3+ in a borosilicate glass has been probed by a combination of laser spectroscopy, structural modeling, and extended x-ray absorption fine structure (EXAFS) spectroscopy. The Stark splitting for the Cm f–f state transitions is significantly larger than the inhomogeneous line broadening that…

Luminescence Properties of Advanced MaterialsGlass properties and applicationsX-ray Spectroscopy and Fluorescence Analysis

Magnetic and magnetostrictive properties in amorphous (Tb0.27Dy0.73)(Fe1−xCox)2 films

Nguyễn Hữu Đức、K. Mackay、J. Betz 等 4 位作者2000-01-15Journal of Applied Physics

Magnetic and magnetostrictive properties have been investigated for amorphous (Tb0.27Dy0.73)(Fe1−xCox)2 thin films. An increase in the 3d magnetic moment due to the enhancement of T–T interactions in substituted (Fe, Co) alloys was found. This leads to stronger R–(Fe, Co) exchange energies and then to enhancements of…

Magnetic properties of thin filmsMetallic Glasses and Amorphous AlloysMagnetic Properties and Applications

Electronic structure of layered perovskite-relatedSr1−yLayNbO3.5−x

C. A. Kuntscher、Stefan Gerhold、N. Nücker 等 10 位作者2000-01-15Physical review. B, Condensed matter

The electronic properties and the crystal structure of layered perovskite-related niobates ${\mathrm{Sr}}_{1\ensuremath{-}y}{\mathrm{La}}_{y}{\mathrm{NbO}}_{3.5\ensuremath{-}x}$ can be tuned by gradually changing the oxygen stoichiometry. We have studied the electronic structure of this series in detail by angle-integ…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsElectronic and Structural Properties of Oxides

A novel silk-based segmented block copolymer containing GlyAlaGlyAla ?-sheets templated by phenoxathiin

Osman Rathore、Michael J. Winningham、Dotsevi Y. Sogah2000-01-15Journal of Polymer Science Part A Polymer Chemistry

A novel segmented block copolymer, containing polyethylene glycol segment and GlyAlaGlyAla sequence derived from B. mori silk, has been prepared as a model for silk-based materials using both solution and interfacial techniques. Inherent viscosity, size exclusion chromatography, and light-scattering measurements gave…

RNA Interference and Gene DeliveryChemical Synthesis and AnalysisSilk-based biomaterials and applications

Photoconductivity of nitrogen-modified hydrogenated tetrahedral amorphous carbon

Adelina Ilie、O. Harel、N. M. J. Conway 等 6 位作者2000-01-15Journal of Applied Physics

The changes in the photoconductivity of hydrogenated tetrahedral amorphous carbon (ta-C:H) with nitrogen incorporation were studied. Low level nitrogen incorporation improves the photoconductivity, by shifting the Fermi level upwards in the band gap. Films with a photosensitivity of about 200 at room temperature under…

High-pressure geophysics and materialsSemiconductor materials and devicesDiamond and Carbon-based Materials Research

Novel thermoplastic elastomers. III. Synthesis, characterization, and properties of star-block copolymers of poly(indene-b-isobutylene) arms emanating from cyclosiloxane cores

Jung S. Shim、Joseph P. Kennedy2000-01-15Journal of Polymer Science Part A Polymer Chemistry

Novel thermoplastic elastomers (TPEs) consisting of poly(isobutylene-b-indene) (PIB-b-PInd) arms radiating from hexamethylcyclohexasiloxane (D) cores were prepared, characterized, and their properties investigated. The syntheses of these star-blocks involved the linking by hydrosilation of PInd-b-PIBCH2CHCH2 prearm…

Polymer Nanocomposites and Propertiesbiodegradable polymer synthesis and propertiesSilicone and Siloxane Chemistry

Quenching Mechanisms in Bichromophoric, 310-Helical Aib-Based Peptides, Modulated by Chain-Length-Dependent Topologies

B. Pispisa、Lorenzo Stella、Mariano Venanzi 等 8 位作者2000-01-15Macromolecules

The photophysical and structural features of a series of linear, Aib-based peptides were investigated in methanol solution. These compounds have the general formula P(Aib) n N, where Aib is α-aminoisobutyric acid, N naphthalene, and P the monomethylated protoporphyrin IX, the two latter molecules being covalently atta…

Photosynthetic Processes and MechanismsPorphyrin and Phthalocyanine ChemistryPhotochemistry and Electron Transfer Studies

Microscopic structure of the substitutional Al defect in α quartz

Marco Magagnini、Paolo Giannozzi、Andrea Dal Corso2000-01-15Physical review. B, Condensed matter

First-principles pseudopotential calculations are reported for the lattice distortion and electronic properties of the Al substitutional defect in $\ensuremath{\alpha}$ quartz. We determine microscopical properties of the center such as Al coordination, symmetry of the distorted lattice and defect-induced electronic s…

High-pressure geophysics and materialsAcoustic Wave Resonator TechnologiesSolid-state spectroscopy and crystallography

Raman spectroscopy of phenylcarbyne polymer films under pulsed green laser irradiation

Yongfeng Lu、Su Huang、Z. Sun2000-01-15Journal of Applied Physics

The polycarbyne polymer films were coated on silicon substrates and then irradiated by a pulsed Nd:yttrium–aluminum–garnet laser (λ=532 nm) with various fluences in argon gas atmosphere. Significant changes in microstructures and chemical bonding (sp3/sp2) during laser treatment were investigated by Raman spectroscopy…

Metal and Thin Film MechanicsDiamond and Carbon-based Materials ResearchSilicone and Siloxane Chemistry

Molecular Structure of an Fe(IV) Species: {[Fe(TTP)]2N}SbCl6

Ming Li、Maoyu Shang、N. Ehlinger 等 5 位作者2000-01-15Inorganic Chemistry

The molecular structure of the formal iron(IV) porphyrinate derivative, [[Fe(TTP)]2N]SbCl6 (TTP = tetratolylporphyrinate), is reported. The structural parameters are compared to the previously reported species [Fe(TPP)]2N, in which the iron oxidation state is +3.5. Both the equatorial and axial bond distances in [[Fe(…

Magnetism in coordination complexesPorphyrin and Phthalocyanine ChemistryOrganic and Molecular Conductors Research

Calculation of helical twisting power for liquid crystal chiral dopants

Melanie J. Cook、Mark R. Wilson2000-01-15The Journal of Chemical Physics

The helical twisting power βM determines the pitch of the chiral nematic phase produced when a nematic liquid crystal is doped with a low concentration of chiral solute molecules. Molecules with large βM values have potential applications in electro-optic displays and in optical data storage. This paper describes a ne…

Liquid Crystal Research AdvancementsOptical Polarization and EllipsometryMolecular spectroscopy and chirality

Atomic-scale modeling of the ion-beam-induced growth of amorphous carbon

Maria Kaukonen、R. M. Nieminen2000-01-15Physical review. B, Condensed matter

The results of a detailed molecular-dynamics study of the growth of amorphous carbon $(a\ensuremath{-}\mathrm{C})$ are reported. Carbon atoms with kinetic energies between 10 and 150 eV are deposited on $a\ensuremath{-}\mathrm{C}$ surface originating from bulk $a\ensuremath{-}\mathrm{C}.$ Earlier simulation results of…

Metal and Thin Film MechanicsDiamond and Carbon-based Materials ResearchIon-surface interactions and analysis

Non-exponential kinetic behaviour of confined water

Paola Gallo、M. Rovere、Maria Antonietta Ricci 等 5 位作者2000-01-15Europhysics Letters (EPL)

We present the results of molecular dynamics simulations of SPC/E water confined in a realistic model of a silica pore. The single-particle dynamics have been studied at ambient temperature for different hydration levels. The confinement near the hydrophilic surface makes the dynamic behaviour of the liquid strongly d…

Material Dynamics and PropertiesSpectroscopy and Quantum Chemical StudiesNanopore and Nanochannel Transport Studies

Dynamics of lithium ions in bismuthate glasses

A. Pan、A. Ghosh2000-01-15The Journal of Chemical Physics

The dynamics of lithium ions in lithium bismuthate glasses have been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 323 to 543 K. The composition dependence of the dc (direct current) conductivity has been explained in terms of the structure of bismuthate glasses. The activation e…

Material Dynamics and PropertiesGlass properties and applicationsSolid-state spectroscopy and crystallography

Lifetime- and Color-Tailored Fluorophores in the Micro- to Millisecond Time Regime

Jiyan Chen、Paul R. Selvin2000-01-15Journal of the American Chemical Society

We report the development of compound dyes which have tunable emission wavelengths, from 520 to 680 nm, and simultaneously tunable excited-state lifetimes, ranging from 50 to 500 μs. Future work is expected to extend these ranges yet further. The compound dyes are made of a lanthanide donor with a millisecond lifetime…

Organic Light-Emitting Diodes ResearchPhotochemistry and Electron Transfer StudiesLuminescence and Fluorescent Materials

New Alternating Ferro- and Antiferromagnetic One-Dimensional Complexes. Synthesis, Characterization, Crystal Structure, and Magnetic Properties of [M(4,4‘-dimethylbipyridine)(N3)2]n [M = Cu(II), Mn(II), Ni(II), Fe(II)]

Hao-Yu Shen、Wei‐Ming Bu、En‐Qing Gao 等 7 位作者2000-01-15Inorganic Chemistry

The preparation, X-ray crystal structure, and magnetic properties of alternating 1,1- and 1,3-azido-bridged copper(II) complex [Cu(4,4'-dmbpy)(N3)2]n (1, 4,4'-dmbpy = 4,4'-dimethylbipyridine) have been reported. It crystallizes in triclinic system, space group P1, a = 7.9903(1) A, b = 9.3545(9) A, c = 10.754(2) A, alp…

Metal complexes synthesis and propertiesMagnetism in coordination complexesOrganic and Molecular Conductors Research

1sshake-up excitations in Ge andGeO2by high-energy x-ray photoemission spectroscopy

V. Formoso、A. Filipponi、Andrea Di Cicco 等 6 位作者2000-01-15Physical review. B, Condensed matter

X-ray photoemission spectra of Ge and ${\mathrm{GeO}}_{2}$ have been collected using high-energy photons ${(E}_{\ensuremath{\gamma}}=13.6\mathrm{keV}$ and ${E}_{\ensuremath{\gamma}}=11.85\mathrm{keV}).$ The experiment was carried out using a high brilliance undulator source of the European Synchrotron Radiation Facili…

Semiconductor materials and devicesX-ray Spectroscopy and Fluorescence AnalysisElectron and X-Ray Spectroscopy Techniques